The present invention relates generally to antibacterial coatings for preventing and treating bacterial and microorganism colonization, biofilm formation, and infection involving medical devices and surfaces. More specifically, the present invention relates to systems and methods for forming highly hydrophobic coatings using the reaction of a silyl protected dithiol with a perfluoroarene in the presence of an organocatalyst.
The accumulation of microorganisms on wetted surfaces, or biofouling, is a ubiquitous problem for materials in a broad range of applications such as medical devices, marine instruments, food processing, and even domestic drains. Generally, bacteria initiate biofouling via the formation of biofilms, which are formed of highly ordered adherent colonies, most frequently within a self-produced matrix of extracellular polymeric substance.
There are a variety of implantable devices, including, for example, prosthetic joints, heart valves, artificial hearts, vascular stents and grafts, cardiac pacemakers, defibrillators, nerve stimulation devices, gastric pacers, vascular catheters and ports (e.g., Port-A-Cath). Infection is a potential problem for all implanted medical devices—the surfaces of these implanted materials and devices represent areas of local immunocompromise in which bacterial colonization and subsequent biofilm formation is difficult to diagnose and treat. Biofilms are the main culprit for persistent infections, owing to their treatment resistance, the potential release of harmful toxins, and the ease with which the microorganisms spread, which can lead to malfunction of implantable devices on which they develop (e.g. catheter occlusion) or septic emboli seeding microorganisms in remote sites.
Extreme measures such as removal of the infected implanted device from the patient's body are often the only viable management option. Although disinfection techniques and prophylactic antibiotic treatment are used to prevent colonization during procedures, this practice is not 100% effective in preventing perioperative bacterial colonization. Moreover, the risk of bacterial colonization on a prosthetic joint is present long after its implantation. For example, with S. aureus bacteremia, the risk for colonization on a prosthetic joint approaches 25 percent.
Antibiotic treatments to eliminate colonization and infection associated with implantable substances and devices are limited in their ability to eradicate bacteria and fungi involved in these processes. There are multiple reasons for this, including reduced antibiotic concentration deep inside the biofilm due to limited diffusion, inability of antibiotics in general to eliminate “the last” pathogen cells (usually accomplished by the immune system, which does not function well in the setting of implantable devices), and the ability of microorganisms to persist, i.e., become metabolically inactive and thus functionally relatively resistant to antibiotics. Antibiotic resistance makes treating device-associated infections even more challenging. In fact, antibiotic resistance is frequently encountered with microorganisms that cause device-associated infections (e.g., Enterococci, Staphylococci).
Consequently, considerable efforts were dedicated in recent years to developing antibacterial surfaces. Such surfaces can be classified into two categories: (i) antifouling surfaces that prevent the adhesion of microorganisms and (ii) bactericidal surfaces that trigger bacteria killing. Typical strategies for the design of antibacterial surfaces involve either supramolecular (non-covalent) coating of the surface or modification of the surface (i.e., chemical modification or structuring). Current technologies, however, suffer from poor long-term antibacterial performance and stability, the undesirable development of bacterial resistance, or limited scalability to an industrial setting.